The objective is to ensure that all PO1 projects have suitable participants available in sufficient number to fulfill each project's specific aims. It recruits and identifies participants with verified diagnostic and developmental status and level of readiness appropriate for each project study. To achieve this objective, the core provides three major support services. It will be responsible for: (1) human studies matters (i.e., recruiting participants, obtaining informed consent, consultation with families and treatment teams, etc.); (2) participant assessment (i.e., administering a battery of clinical and behavioral assessments to potential participants, following a thorough review of their psycho-educational record) and baseline preparation; and (3) tracking experimental participation and progress.